Haoyi Li
Staff Software Engineer, Tech Lead Manager at Databricks
Singapore
Summary
🤩
Rockstar🎓
Top SchoolHaoyi Li is a Staff Software Engineer and tech lead manager based in Singapore with 13 years of experience building high-performance developer tooling and distributed systems. He architects scalable infra—most recently Databricks’ elastic CI, Dev Box service, and cloud integration testing platform—while leading a distributed team across five countries and improving developer productivity by multiple factors. A hands-on engineer with deep Scala expertise, he’s the author and maintainer of influential open-source projects (FastParse, uPickle, Mill, scala.rx) and contributes to the Scala compiler and Scala.js ecosystem. His work blends compiler-level performance engineering, build-system design, and pragmatic developer ergonomics—he even implemented Databricks’ internal config language and IDE plugin. Known for turning rough prototypes into production-grade systems, he also runs regular tech talks and introduced org-wide practices like JVM profiling and structured logging.
13 years of coding experience
4 years of employment as a software developer
Bachelors, Electrical Engineering and Computer Science, Bachelors, Electrical Engineering and Computer Science at Massachusetts Institute of Technology
Stackoverflow
15,402reputation
1.8mreached
25answers
143questions
sbt
top-5%
scala
top-5%
jetty
top-5%
Github Skills (46)
javascript10
parser10
python10
abstract-syntax-tree10
parser-combinators10
macros10
testing10
data-serialization10
data-structure10
scala10
serialization10
lang10
compiler-design10
scalajs10
parsing10
Programming languages (15)
Github contributions (5)
com-lihaoyi/mill
Oct 2017 - May 2022
Mill is a fast build tool that supports Java, Scala, Kotlin and many other languages. 2-4x faster than Gradle and 4-10x faster than Maven for common workflows, Mill aims to make your project’s build process performant, maintainable, and flexible
Role in this project:
Back-end Developer
Back-end DeveloperContributions:1 release, 1071 reviews, 890 commits in 4 years 8 months
Contributions summary:Haoyi made several contributions to the Mill build tool, including modifying the `GenIdea.scala` file to mark the Scala library jar as `type=Scala`. They worked on improving the code to avoid compiling just to access compiled code output paths, as well as simplifying build.sc file syntax. Furthermore, they implemented changes to time the entire main method and remove a play-json dependency in favor of upickle.
zincshinymilljvmscala
com-lihaoyi/upickle
Apr 2014 - May 2022
uPickle: a simple, fast, dependency-free JSON & Binary (MessagePack) serialization library for Scala
Role in this project:Back-end Developer
Back-end DeveloperContributions:21 reviews, 452 commits, 251 PRs in 8 years 1 month
Contributions summary:Haoyi primarily worked on a Scala library for JSON and MessagePack serialization, demonstrating a focus on improving the core functionality of the library. The commits reveal efforts to update and refine the internal structures for handling JSON and MessagePack data, including improved index tracking for error reporting. The user also implemented support for parsing various data types and for the serialization of custom data structures.
upickleserializationmessagepackserialization-libraryscala
Find and Hire Top DevelopersWe’ve analyzed the programming source code of over 60 million software developers on GitHub and scored them by 50,000 skills. Sign-up on Prog,AI to search for software developers.